Various observation and photography devices for photographing and observing the surface of a sample are known (e.g., see Patent Literature 1).
Patent Literature 1 will be described with reference to FIG. 12 hereof.
FIG. 12 illustrates the basic principle of a conventional observation and photography device. The surface of a sample 101 is observed using a microscope 102, as shown in FIG. 12. The surface of the sample 101 is photographed using a photography unit 103 attached to the microscope 102 and is recorded in the form of an image.
When the sample 101 is a metal material, the surface of the sample 101 is mirror-finished by a polishing mechanism prior to observation and/or photography.
Various polishing mechanisms for polishing the sample 101 have been proposed (e.g., Patent Literature 2).
Patent Literature 2 will be described with reference to FIG. 13 hereof.
FIG. 13 illustrates the basic principle of a conventional polishing mechanism. The sample 101 is placed on a rotating table 105, as shown in FIG. 13. A polishing liquid 106 containing very small polishing particles is fed from a down-facing nozzle 108 to the sample 101. A polishing liquid 106 containing polishing particles flows over the upper surface of the sample 101 by centrifugal force. The upper surface of the sample 101 is polished by bringing a rotating polishing cloth 107 into contact with the upper surface of the sample 101. Observation is carried out using the microscope 102 indicated by an imaginary line and photography is carried out using the photography unit 103.
A portion of the very small polishing particles bites into the polishing cloth 107 and stays on the polishing cloth 107. The polishing particles are crushed upon use. The broken surfaces are sharp and damage the sample 101 when not removed. Crushed polishing particles are left behind on the upper surface of the sample 101 as well. A portion of the shaved sample damages the sample 101, which roughens the upper surface of the sample 101 and reduces the quality of the sample 101.
Washing or replacing the polishing cloth 107 can prevent a reduction in quality. When the polishing cloth is to be replaced, the polishing mechanism must be stopped; therefor, the operation life of the observation and photography device is reduced.
Moreover, the crushed polishing particles bite into the polishing cloth 107. When the polishing cloth is washed, the polishing particles are scraped off from the polishing cloth 107 using a spatula or a squeegee. The polishing cloth 107 gets damaged by the spatula or squeegee, and time is required to wash away the polishing particles using a large amount of washing liquid.
When washing is carried out, the service life of the polishing cloth 107 is reduced and large amounts of washing liquid are required.
In terms of smoothly and efficiently performing experiments, it is not advantageous for the service life of the polishing cloth to be reduced and for the required amount of washing liquid to be increased. Therefore, there is a need for an observation and photography device allowing the required amount of washing liquid to be reduced.
Polishing has been conventionally carried using electrolysis. The surface of the sample can be smoothed by electrolytic polishing. An electrolytic polishing sheet and electrolytic polishing cloth or electrolytic bath are generally required to perform electrolysis. Therefore, the electrolytic polishing sheet and electrolytic polishing cloth or electrolytic bath must be separately provided, increasing the size of the polishing mechanism. There is a need to reduce the size of the polishing mechanism.
In electrolysis, the surface of the sample becomes fouled by the solute components of the sample. It is possible to prevent polluting by replacing the electrolyte after each use. However, large volumes of electrolyte are required. There is a need to reduce the required amount of electrolyte.
The amount of polishing must be measured in a polishing mechanism. The amount of polishing is very low; i.e., 100 nm to several tens of microns. A measurement device for measuring the amount of polishing is supported on the machine stand via a support, and when the support deforms, errors occur in the measurement value relating to the amount of polishing. Also, when the sample stand (rotating table, or the like) on which the sample is placed deforms, errors occur in the measurement value relating to the amount of polishing.
In a conventional structure, it is difficult to increase the precision for measuring the amount polishing. Consequently, there is a need for a structure capable of increasing the precision for measuring the amount of polishing.
The surface of the sample may be corroded by chemicals prior to observation of the sample surface. This method is referred to as chemical etching.
When the corrosive liquid splashes and makes contact with the microscope and/or the device for measuring the amount of polishing, the microscope and/or the device for measuring the amount of polishing can be damaged, which is a problem that needs to be addressed.
In FIG. 13, the microscope 102 is adjusted so that a focal point is established on the upper surface of the sample 101. Because adjusting the microscope 102 is laborious, the focal point is adjusted prior to observation.
However, the surface is lowered when the sample 101 is repeatedly polished with the polishing cloth 107. The focal point falls out of alignment when the surface is lowered, and the image becomes blurred. There is a need to obtain a sharp image even when the surface is lowered.
Photographs are taken while the microscope 102 is moved along the surface of the sample 101, polishing is carried out, and photographs are taken while the microscope 102 is repeatedly moved along the surface of the sample 101. The acquired images can be layered to produce a stereoscopic image.
The microscope 102 may not accurately return to its original position due to mechanical error such as backlash. The image becomes less clear when such error occurs.
There is a need to obtain a clear image even when the microscope 102 moves.